Metal Star Puzzle




About: I am an engineer and I like to build things. I am well versed in drafting and solid modeling and enjoy a nice challenging build.

I like puzzles. It is fun to take something apart and try to put it back together again. I can spend days sometimes weeks trying to figure out a puzzle if it provides a formidable challenge.

After enjoying some puzzling, I had an inkling to make my own. I don't claim this design as my own, it has been around for some time. I just think it looks really cool and also makes a good paper weight. The following is my endeavors to make a metal star puzzle.

Step 1: Design

The metal star puzzle consists of 6 interlocking pieces. All of them are clones of one another. I have seen some designs where you have 3, 2, and 1; I find that version of this puzzle to be not quite as elegant as this one I'm making (the solution anyways).

I designed the piece of the puzzle in Solidworks. My intention was to 3d print a sand mold that I could use to cast these into aluminum. After designing the one piece, I repeated it and modeled a negative of it, creating a model of the mold design.

The files for the mold and the 1 piece are attached to this step. Feel free to use them for 3d printing purposes or whatever you'd like.

Step 2: Printing the Mold

After completing the mold design, I uploaded the files to my companies sand printer and built 2 molds, 4 halves in total. You can view my other instructables for more details on the molding and printing processes I used. It took 5 hours to print the mold, most of that time is just waiting for the glue to fully bond with the sand grains.

Step 3: Casting and Cleaning

Once the mold was printed, it was brought out to the melting line and prepped for pouring. Weights are placed on it so the top half of the mold does not lift off and spill metal out the sides. I pour this out of 319 aluminum at 1300F, very weak metal but strength is not important for this project.

After the metal has cooled, the castings were broken out of the molds, cut from the feeding system, ground down, and sandblasted to a consistent finish. The casting and cleaning process took 2 hours.

Step 4: Disassembly

Once made taking it apart is very simple......

Step 5: Assembly

.... its putting it back together that may require a little motivation.

I am not posting the solution, I always like trying to figure things out on my own so I encourage you to as well if you decide to make some sort of iteration of this one. I can give you a hint though. The pieces are not assembled one at a time.

If you like this, please vote for it in the metal contest.



    • Sensors Contest

      Sensors Contest
    • Pets Challenge

      Pets Challenge
    • Fandom Contest

      Fandom Contest

    5 Discussions


    1 year ago

    Hello. Finally i found this. Unfortunately in my country there isn't this kind of devices to create 6 piece 3D star puzzle, and in the internet i couldn't find anywhere star made from aluminium alloy. So is it possible to order it from you, so you could make it and i'll pay to your bank account. And if it's possible how much will it cost? Looking forward to your respond to my e-mail:


    2 years ago

    this was really cool but how do you do the other mind games in the background of the first picture?


    2 years ago

    Awesome 3D printed mold for this great puzzle! What type of metal did you use? What 3D printer did you use?

    1 reply

    Reply 2 years ago

    The puzzle is made of 319 aluminum. Nothing special about that particular alloy. The printer is a Z printer 310 plus, not made or supported anymore unfortunately.


    2 years ago

    Very cool project. I wish I had a sand printer.